1. Field of the Invention
The present invention relates to portable lighters in which liquefied gas fuel is ignited by means of a discharge spark, and particularly to a portable lighter having an igniter device equipped with a safety lock mechanism.
2. Detailed Description of the Prior Art
There are known portable lighters including cigarette lighters, micro torches and the like (herein referred to as portable lighters) which use high voltage electrical generators utilizing piezo-electric elements as a spark source distinguished from lighters which ignite liquefied gas fuel by means of a discharge spark. The present type of portable lighter generates a high voltage by impacting a piezo-electric element placed between electrodes, close to a gas discharge nozzle, generating a spark. The spark in turn ignites liquefied gas discharged from the nozzle.
FIG. 1 shows a cigarette lighter as a conventional example of this type of portable lighter.
Normally, a lighter main body 1 includes a liquefied gas fuel tank installed thereinside and a high voltage electrical generator 2 on its side. The high voltage electrical generator 2 is composed of a rectangular fixed member 2a and a movable member 2b. The fixed member 2a contains a piezo-electric element 2c and an impact hammer 2d releasable positioned over that element. The movable member 2b is hollow containing a coil spring 2e positioned between the hammer 2d and the top plate.
In the conventional cigarette lighter, shown in FIG. 1, a plastic casing 3 has an open upper portion integrally formed on the side of the lighter main body 1. The high voltage electrical generator 2 is housed in this casing 3.
The movable member 2b is positioned on its upper side and the fixed member 2a is inserted lengthwise into the casing 3. An operating button 4 is mounted on top of the movable member 2b positioned on the upper side of the lighter main body 1 away from the opening of the casing 3. This operating button 4 is integrally formed with a cover 5 of the high voltage electrical generator 2 shielding the opening of the casing 3.
A lead wire 6 of the high voltage electrical generator 2 is fed upward from the piezo-electric element 2c, diagonally to a nozzle 8 of a combustion valve 7 mounted on the upper portion of the lighter main body 1. The tip end 9 of this lead wire 6 functions as a positive (+) electrode that generates a discharge spark between itself and the nozzle 8 that also functions as a negative (-) electrode. Reference numeral 10 designates a lever type valve switch member and is arranged extending across the lower side of and engagable by the operating button 4 and the step portion at the lower side of the valve 8. In the cigarette lighter configured as above, the lighter main body 1 is grasped while the thumb is placed on the operating button 4. When the operating button 4 is pressed by the finger pressure of the thumb, the movable member 2b compresses the coil spring 2e and opens the combustion valve 7 by pressing down the valve switch member 10.
Next, the hammer 2d releases after the movable member 2b sufficiently compresses the coil spring 2e. The piezo-electric element 2c located on the lower side of the movable member 2b is then struck by the released hammer 2d and a high voltage is generated. This high voltage discharges between the tip end 9 of the lead wire 6 and the nozzle 8, generating a spark which ignites the liquefied gas discharged from the nozzle 8.
The combustion of gas fuel is maintained while pressing the operating button 4. When the thumb releases the operating button 4, the returning force of the coil spring 2e returns both the movable member 2b, and the valve switch member 10 to their original positions, the combustion valve 7 closes which in turn stops the flow of combustion gas. The hammer 2d is returned by the return movement of the movable member 2b having a means for holding the hammer 2d when returning.
In a cigarette lighter that can use the generation of high voltage to repeatedly ignite liquefied gas from the opening of the combustion valve 7 just by using finger pressure to press down the operating button 4 in this manner, the object of the cigarette lighter can be achieved which is to allow one-handed operation.
Because, however, it is not necessary to strongly press down the operating button 4, the danger exits that the operating button 4 will be inadvertently pressed down at some time causing the lighter to ignite unexpectedly. Further, because a strong grasping or finger pressure force is not required, there are many occasions when the lighter may ignite even with children who have no hand strength. In particular, in households where cigarette lighters are used often, there are many chances when curious children may take a lighter left on a tabletop in the house and copy the way adults use the lighter when they are not supervised. This is a very serious problem that may result in burns or fires.
In the United States, companies are responsible for adding safety mechanisms which do not allow children to use the lighter as measures (child resistance) to prevent the dangers associated with portable lighters such as cigarette lighters and children.
Normally, when considering a safety mechanism, a more complicated construction compared to previous lighters is imagined to ignite the lighter such as a two-action or three-action operation. If the number of operations is increased however, ordinary ignition becomes troublesome and a construction in which both hands are used makes it difficult to use the lighter for cigarettes.
Moreover, children have very keen powers of observation and when adults follow an operations procedure to use a lighter effortlessly without thinking, the steps of the operation from the eyes of a child can be memorized while watching the adult. Consequently, if a lighter is left on a table, there is the possibility that a child may use that lighter, release the safety mechanism and ignite the lighter.